Can't attach material to imported SVG in python
Instead of:

        #two from my attempts, nothing works, material is correct            
        bpy.data.objects[emb_name].materials = [mat]  
        bpy.data.objects[emb_name].setMaterials([mat])  
        #end of not-working code


Try:

        bpy.data.objects[emb_name].active_material = bpy.data.materials['Z']


If this still does not work, you may need to look at adding a material slot first.

        bpy.ops.object.material_slot_add()